Investments In Unconsolidated Affiliates And Related Party Transactions (Narrative) (Details) (USD $) In Millions, unless otherwise specified	3 Months Ended			12 Months Ended
	Dec. 31, 2011	Sep. 30, 2011	Dec. 31, 2010	Dec. 31, 2011	Dec. 31, 2010	Dec. 31, 2009
Debt obligation	$ 64		$ 66	$ 64	$ 66
Impairment charge					11	21
Proceeds from sale of ownership interest			165
Amount of common shares included in net proceeds			87
Asset impairment charges	(59)	(301)		335	726	420
Equity Method Investment, Realized Gain (Loss) on Disposal				11	103	(21)
Distributions from equity investments				149	111	83
Cash proceeds from exercise of cash settlement option					184
INDU Solar Holdings [Member]
Ownership interest	50.00%			50.00%
Commercial Power [Member]
Ownership interest	50.00%			50.00%
Suez-DEGS Solutions [Member]
Ownership interest	49.00%			49.00%
International Energy [Member]
Ownership interest	25.00%			25.00%
Asset impairment charges						18
Q-Comm Corporation [Member]
Ownership interest			30.00%		30.00%
Equity Method Investment, Realized Gain (Loss) on Disposal			109
Crescent [Member]
Ownership interest	50.00%			50.00%
DukeNet [Member]
Ownership interest			50.00%		50.00%
Equity Method Investment, Realized Gain (Loss) on Disposal			139
U.S. Franchised Electric And Gas [Member]
Donations				3	1	11
Trade payable to Advance SC LLC	3			3
Attiki [Member]
Carrying value of investment in affiliates	$ 64		$ 66	$ 64	$ 66
Alinda Capital Partners Interest In DukeNet [Member]
Ownership interest			50.00%		50.00%
Duke Energy Interest In DukeNet [Member]
Ownership interest			50.00%		50.00%